Another key feature of lax extensions is that they induce
canonical modalities, generalizing Moss' coalgebraic
logic [1]}:
[Lax Nabla [2]}]
The lax nabla of \(L\)  is the family of functions
\(\nabla ^L_X : T\mathcal {Q} X & \rightarrow \mathcal {Q} T^\mathsf {op}X\\\Phi \quad &\mapsto \lbrace  t\in TX \mid ( t, \Phi ) \in L(\in _X) \rbrace ,\) 
